1. Field of the Invention
This invention generally relates to a sheet feeder for feeding sheets of material, such as paper, to an apparatus which typically handles a number of consecutive sheets of the material at a regular interval of time. Such an apparatus could be, for example any type of printing machine, or printing press. In general, the material stock is provided in the form of a stack of sheets of the material, placed in the vicinity of the sheet feeder, wherein the sheet feeder, adjacent the material stack, can have a tape roller with corresponding timing rollers. For conveying the sheets from the tape rollers to a positioning guide, the sheet feeder can have a number of continuously conveying transport tapes to which transport rollers can be assigned. The transport tapes and the corresponding transport rollers convey overlappingly fed sheets to a front guide, wherein the last transport rollers in the sheet feed direction, provided upstream of the front guide, can be adjustable with respect to the sheet format, or sheet size, of the sheets being processed.
2. Background Information
With modern sheet-fed printing machines, different sheet formats have to be printed, with the sheet formats differing from one another in size by about 50 percent and more. In order to be able to produce a high-quality print at high transport speeds it is of great importance that the sheets taken from the feed stack be precisely conveyed towards the front guides. However, with known printing machines this exact transport cannot always be guaranteed without additional manual input, in particular, when sheet formats having a very small size are being processed.